This is the most important point in the whole post: As your career progresses, each unit of work you do should generate more and more results. There are many ways to get this leverage, such as capital, technology, brand, network effects, and managing people

That goes straight to the concept of scalability. Usually we talk about it in terms of businesses scaling or benefiting from economies of scale, but this is talking about scalability on a personal level. Not to be understated.